1. Field of the Invention
The present invention relates to a radiation detecting device that detects as an electric signal a radiation, which is employed in a medical diagnosis device, a nondestructive test device or the like, and a method of manufacturing the radiation detecting device. In the present invention, electromagnetic waves such as x-rays, α-rays, β-rays and γ-rays are also included in the radiation.
2. Related Background Art
Up to now, an x-ray film system having a phosphor screen having x-ray phosphors therein and a both-side coated sensitizing agent has been generally employed for electrography. However, in recent years, from the viewpoints of such advantages that an image characteristic of a digital radiation detecting device having an x-ray phosphor layer and a two-dimensional sensor panel is excellent, and data is shared by downloading the data into a networked computer system because the data is digital data, the digital radiation detecting device has been actively researched and developed, and various patent applications for the digital radiation detecting device have been filed.
Among those digital radiation detecting devices, there has been known, as a device high in the sensitivity and sharpness, a radiation detecting device in which a radiation detection scintillator having a phosphor layer on a substrate that transmits the radiation is bonded onto and integrated with a sensor panel having a plurality of photoelectric conversion elements arranged on a transmittable support substrate and electric elements such as TFTs arranged, in the gaps of the respective photoelectric conversion elements, as disclosed in U.S. Pat. No. 5,793,047 and U.S. Pat. No. 6,469,305.
In the above-mentioned conventional example, the phosphors are laminated on a front surface of the transmittable support substrate on which the photoelectric conversion elements are arranged, whereas a light absorption layer is laminated on a back surface of the transmittable support substrate. In addition, the surface on which the light absorption layer is disposed is bonded to a base through an adhesive.
The light absorption layer on the back surface of the transmittable support substrate of the sensor panel as disclosed in the above conventional example is provided for the purposes of antireflection and light shielding, and solves such a problem that a light to be received such as a light emitted from the phosphor layer is reflected by portions other than the photoelectric conversion portion, such as the back surface of the transmittable support substrate or an edge portion of the substrate, to be received. The light absorption layer is provided by forming a resin directly on the transmittable support substrate through coating and printing processes.
The radiation detection scintillator of the conventional example suffers from the following problems during the process or in an acceleration test of a long-term durability test.
(1) The respective structural layers are displaced due to a heat in a heat history during the process or during the durability, with the result that there arises such a problem that the respective layers are warped due to the displacement, an internal stress is applied to the phosphors and the respective structural layers, and a layer weak in the stress is destroyed or peeled off due to the internal stress.
(2) The respective structural layers are displaced due to a heat in the heat history during the process. Up to now, the sensor panel has been warped by the displacement because a large number of layers are formed on the front surface of the sensor panel in which the photoelectric conversion elements are arranged. There may arise such problems as an improper installation position or a connection failure due to the warp of the sensor panel in the case where a crimp type terminal is installed on an electrode lead pad potion on the panel for electric wiring connection. Also, in some cases, the connection portion is damaged, and the connection fails due to the warp stress of the sensor panel during the acceleration durability.
(3) The sensor panel is flowed while the panel is mounted on a carrying holder, and in the case where the support substrate back surface comes in contact with a surface of the carrying holder, the light absorption is grazed and damaged or peeled off due to a mechanical friction in the case of the conventional material, with the result that the light shielding on the defective portion becomes insufficient, to thereby increase the image defects.
The conventional examples disclosed up to now teach nothing of the structural material of the panel back surface side and the laminating manner taking the stress after laminating into consideration.